Installation of battery for the hottest electric v

Installation of electric vehicle battery

the battery is generally used in series, that is, the positive pole of one battery is connected to the negative pole of another battery, connecting all batteries together, and finally the remaining positive and negative terminals are connected to the corresponding wiring of the electric vehicle. The electric machine, controller, instrument, etc. of the electric vehicle are the electrical load of the battery

electric vehicles generally have battery boxes, which can be divided into slash type, rear plug-in type and chassis type installation from the installation position, and their structural shapes are various. Each electric vehicle factory has its own characteristics. As shown in the figure, the battery box is generally made of engineering plastic, which has good strength, light weight and convenient installation. The battery box is generally composed of bottom slot, upper cover, battery contact point, charging socket, trolley lock, etc. The bottom groove is fastened with the upper cover and fastened with self tapping screws or bolts. The battery box is designed according to the model and specification of the battery, and its good heat dissipation performance should be considered in the design of the whole vehicle

charging of electric vehicle battery

"the battery is not used but charged", this statement is by no means alarmist. The charging performance of the battery plays a decisive role in the service life and performance of the battery, which must be paid attention to

1. Requirements of battery on charging process

understanding the basic requirements of battery on charging process is the basis of analyzing various charging technologies. The basic requirements of the battery for charging are that the charging current should be less than or equal to the charging current that the battery can receive. Otherwise, the excess current will cause the electrolyte to be consumed too quickly, resulting in the following hazards:

increase the water loss rate of the battery, increase the maintenance workload, and cause the early failure of the battery for the maintenance free battery; Produce acid mist, cause environmental pollution and endanger workers' health; The charging efficiency is reduced, resulting in a serious waste of energy

the charging process is the reverse reaction process of the discharge electrochemical reaction. If the charging electrochemical reaction process is carried out in an ideal state, this process should be the reverse reaction of each other, that is, the charged electricity and the discharged electricity should be basically equal. However, under the condition of serious gas evolution, the electric energy consumed in the effective charging electrochemical reaction process is less than 40% of the total electric energy, that is, more than 60% of the electric energy is wasted

the generation of gas accumulates in the porous electrode of the battery, reducing the contact area between the electrolyte and the porous electrode, that is, the electrochemical reaction interface of charging is greatly reduced, which reduces the speed of charging chemical reaction, makes charging very difficult, and prolongs the charging time

serious gas evolution will damage the battery: ① the generation of a large amount of gas has a scouring effect on the active substances on the electrode plate, making the active substances easy to loosen and fall off. ② Under high polarization voltage, the grid of the positive plate will produce serious corrosion and generate PB02. This kind of corrosion is completely different from the PB02 stored in the electrochemical student. It is an irreversible oxide with poor conductivity, which will deform and embrittle the grid and lose its skeleton and conductivity. Therefore, overcharge should be prevented as much as possible during charging

if the charge is insufficient for a long time, the unreacted active substance will produce irreversible high positive large particle pbs04 grains (i.e. irreversible sulfation), which will reduce the capacity of the battery, increase the resistance of internal coordination with signal comparison, component exchange and other methods, increase the difficulty of charging, and cause early damage to the battery. Therefore, the battery should be fully charged to prevent irreversible sulfation

2. Selection of charging frequency

the charging depth of battery has a great influence on the cycle life, which basically changes exponentially. This is because the positive active substance is PB02, which has low binding fastness. It is converted into pbs04 when discharging and PbO2 when charging, and the volume of PbSO4 is much larger than that of PbO2 (its volume ratio is about 2:1). Therefore, for the positive plate, the active material will expand and contract repeatedly, so that its leaf spring support method with lifting lugs, such as the connection between 1 particles, will gradually fall off, so that the battery active material will lose its discharge characteristics and become "anode mud", so that the battery performance will decline until the end of its life. The deeper the discharge depth, the greater the expansion and contraction, the greater the damage to the binding force of active substances, and the shorter the service life; Otherwise, the cycle life is longer

theoretically, when using the battery, try to avoid deep discharge, and do shallow discharge and frequent charging, provided that there is a specially matched charger to match it. However, in actual use, because the battery charging is affected by the charger performance, the dispersion of the battery itself, the charging habits and the charging speed, the voltage of the charger is relatively high to create some pieces that can be combined into an open and customized 3D skeleton in the mold, and there is more or less overcharging. In particular, most of the charging is carried out at night, and the time is generally hours, with an average of about 8 hours. If it is shallow discharge, its charging will soon reach the end, when the charging efficiency becomes low, and overcharging will occur. Long overcharge time and frequent charging will greatly affect the battery life due to charging

the optimal charging requirements depend on the actual situation. The charging frequency should be determined by referring to the usual operating frequency, mileage, instructions provided by the battery factory, and the performance of the supporting charger. According to the situation of most users, it is best to charge the battery once when the discharge depth is 50%-70%, so as to achieve the best effect of battery life. In actual use, it can be converted into riding mileage, and the provisions of this standard can be recharged by invoking it in this standard when necessary

3. Influence of temperature on charging

the battery runs in high temperature season, and there is mainly the problem of overcharge. When the temperature of the battery increases, the activity of each active substance increases, and as soon as the positive oxygen evolution potential decreases, the negative oxygen evolution potential also decreases (negative value decreases). Therefore, during charging, the charging reaction speed is fast, the charging current is large, and the charging voltage required during charging is low. In order to prevent excessive charging voltage, the temperature of the battery should be reduced as far as possible to ensure good heat dissipation, prevent charging after exposure to the hot sun, and keep away from heat sources

at low temperature, the activity of each active substance of the battery decreases, and the dissolution of Pb on its electrode becomes difficult. It is difficult to supplement after consuming Pb during charging. The charging current decreases significantly. The charging receiving current of the positive plate at -20 ℃ is only 70% of that at room temperature, while the negative charging is affected by the expansion agent, and the charging receiving capacity at low temperature is lower. The charging receiving current at -20 ℃ is only 40% of that at room temperature. Therefore, charging at low temperature mainly has the problems of poor charging acceptance and insufficient charging, which requires increasing the charging voltage and extending the charging time. The improvement of low temperature performance should mainly start with the negative electrode. Heat preservation and antifreeze measures should be taken when using at low temperature, especially when charging, it should be placed in a warm environment, which is conducive to ensuring sufficient electricity, preventing the production of irreversible sulfuric acid, and extending the service life of the battery

during the storage and use of the battery, the activation charge can be carried out regularly, that is, the so-called balanced charge, which is very beneficial to prevent the irreversible sulfation of the battery, and is very beneficial to the service life of the battery, which is worth advocating. (end)